Can high levels of stress really make you age faster? That seems to be the case judging by all the gray hair President Obama has spouted since his inauguration. Researchers, though, have more scientific ways to measure aging - using telomeres - the caps at the end of our cell's chromosomes that protect DNA from damage. These caps shorten over time, and a new study suggests that a common form of anxiety is associated with short telomeres and perhaps an earlier risk of dying.

Brigham and Women's Hospital researchers looked at data from 5,200 women participating in the Nurses' Health Study and found that women with high levels of phobic anxiety - an exaggerated fear of crowds, heights, enclosed spaces, and certain social situations - had shorter telomeres on average compared with those of the same age who didn't have this anxiety disorder.

The difference in telomere length was equivalent to women of the same chronological age being six years apart on the cellular level, according to Dr. Olivia Okereke, a psychiatrist at Brigham and Women's Hospital who led the study. Previous research has tied telomere length to aging: Long telomeres have been associated with a lower risk of developing cancer and heart disease, as well as of dying at an earlier age.

"Those who have phobic anxiety tend to develop symptoms during childhood and their symptoms are usually chronic and long-lasting," Okereke said.